A Novel Combined Approach to Better Predict Sealing Performance of Luer Lock Connectivity.

Luer systems, for example Luer-needle hub with syringe's Luer cone tip and its Luer lock Adapter, are common interface on medical devices. One of the key questions in this application is about the safety guaranty and dose accuracy. It is then crucial to study the sealing between these elements. In this study we combine the use of Finite Element Analysis (FEA) and Multiscale Contact Mechanics (MCM) to analyze the connectivity and sealing performance of a glass syringe and a plastic needle Luer hub.This methodology has been applied before to the contact between glass and rubber and this is the first time that it is used for the contact between glass and plastic materials. The use of FEA allows to calculate the contact pressures and the nominal area of contact. The surface topographies of the two surfaces were measured, over a wide wavelength range (mm to nm). Subsequently, the air and liquid interfacial flow (leakage) is calculated using Persson's MCM theory which considers the roughness and elasto-plasticity of the interfacial surfaces. The theoretical predictions are compared to experimental leak measurements by pressure decay method. Further analysis is conducted, evidencing the key features that are responsible for a good sealing.